user.c

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/*-------------------------------------------------------------------------
 *
 * user.c
 *    Commands for manipulating roles (formerly called users).
 *
 * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/backend/commands/user.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "access/genam.h"
#include "access/htup_details.h"
#include "access/table.h"
#include "access/xact.h"
#include "catalog/binary_upgrade.h"
#include "catalog/catalog.h"
#include "catalog/dependency.h"
#include "catalog/indexing.h"
#include "catalog/objectaccess.h"
#include "catalog/pg_auth_members.h"
#include "catalog/pg_authid.h"
#include "catalog/pg_database.h"
#include "catalog/pg_db_role_setting.h"
#include "commands/comment.h"
#include "commands/dbcommands.h"
#include "commands/seclabel.h"
#include "commands/user.h"
#include "libpq/crypt.h"
#include "miscadmin.h"
#include "storage/lmgr.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/syscache.h"
#include "utils/timestamp.h"

/* Potentially set by pg_upgrade_support functions */
Oid         binary_upgrade_next_pg_authid_oid = InvalidOid;


/* GUC parameter */
int         Password_encryption = PASSWORD_TYPE_MD5;

/* Hook to check passwords in CreateRole() and AlterRole() */
check_password_hook_type check_password_hook = NULL;

static void AddRoleMems(const char *rolename, Oid roleid,
                        List *memberSpecs, List *memberIds,
                        Oid grantorId, bool admin_opt);
static void DelRoleMems(const char *rolename, Oid roleid,
                        List *memberSpecs, List *memberIds,
                        bool admin_opt);


/* Check if current user has createrole privileges */
static bool
have_createrole_privilege(void)
{
    return has_createrole_privilege(GetUserId());
}


/*
 * CREATE ROLE
 */
Oid
CreateRole(ParseState *pstate, CreateRoleStmt *stmt)
{
    Relation    pg_authid_rel;
    TupleDesc   pg_authid_dsc;
    HeapTuple   tuple;
    Datum       new_record[Natts_pg_authid];
    bool        new_record_nulls[Natts_pg_authid];
    Oid         roleid;
    ListCell   *item;
    ListCell   *option;
    char       *password = NULL;    /* user password */
    bool        issuper = false;    /* Make the user a superuser? */
    bool        inherit = true; /* Auto inherit privileges? */
    bool        createrole = false; /* Can this user create roles? */
    bool        createdb = false;   /* Can the user create databases? */
    bool        canlogin = false;   /* Can this user login? */
    bool        isreplication = false;  /* Is this a replication role? */
    bool        bypassrls = false;  /* Is this a row security enabled role? */
    int         connlimit = -1; /* maximum connections allowed */
    List       *addroleto = NIL;    /* roles to make this a member of */
    List       *rolemembers = NIL;  /* roles to be members of this role */
    List       *adminmembers = NIL; /* roles to be admins of this role */
    char       *validUntil = NULL;  /* time the login is valid until */
    Datum       validUntil_datum;   /* same, as timestamptz Datum */
    bool        validUntil_null;
    DefElem    *dpassword = NULL;
    DefElem    *dissuper = NULL;
    DefElem    *dinherit = NULL;
    DefElem    *dcreaterole = NULL;
    DefElem    *dcreatedb = NULL;
    DefElem    *dcanlogin = NULL;
    DefElem    *disreplication = NULL;
    DefElem    *dconnlimit = NULL;
    DefElem    *daddroleto = NULL;
    DefElem    *drolemembers = NULL;
    DefElem    *dadminmembers = NULL;
    DefElem    *dvalidUntil = NULL;
    DefElem    *dbypassRLS = NULL;

    /* The defaults can vary depending on the original statement type */
    switch (stmt->stmt_type)
    {
        case ROLESTMT_ROLE:
            break;
        case ROLESTMT_USER:
            canlogin = true;
            /* may eventually want inherit to default to false here */
            break;
        case ROLESTMT_GROUP:
            break;
    }

    /* Extract options from the statement node tree */
    foreach(option, stmt->options)
    {
        DefElem    *defel = (DefElem *) lfirst(option);

        if (strcmp(defel->defname, "password") == 0)
        {
            if (dpassword)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options"),
                         parser_errposition(pstate, defel->location)));
            dpassword = defel;
        }
        else if (strcmp(defel->defname, "sysid") == 0)
        {
            ereport(NOTICE,
                    (errmsg("SYSID can no longer be specified")));
        }
        else if (strcmp(defel->defname, "superuser") == 0)
        {
            if (dissuper)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options"),
                         parser_errposition(pstate, defel->location)));
            dissuper = defel;
        }
        else if (strcmp(defel->defname, "inherit") == 0)
        {
            if (dinherit)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options"),
                         parser_errposition(pstate, defel->location)));
            dinherit = defel;
        }
        else if (strcmp(defel->defname, "createrole") == 0)
        {
            if (dcreaterole)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options"),
                         parser_errposition(pstate, defel->location)));
            dcreaterole = defel;
        }
        else if (strcmp(defel->defname, "createdb") == 0)
        {
            if (dcreatedb)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options"),
                         parser_errposition(pstate, defel->location)));
            dcreatedb = defel;
        }
        else if (strcmp(defel->defname, "canlogin") == 0)
        {
            if (dcanlogin)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options"),
                         parser_errposition(pstate, defel->location)));
            dcanlogin = defel;
        }
        else if (strcmp(defel->defname, "isreplication") == 0)
        {
            if (disreplication)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options"),
                         parser_errposition(pstate, defel->location)));
            disreplication = defel;
        }
        else if (strcmp(defel->defname, "connectionlimit") == 0)
        {
            if (dconnlimit)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options"),
                         parser_errposition(pstate, defel->location)));
            dconnlimit = defel;
        }
        else if (strcmp(defel->defname, "addroleto") == 0)
        {
            if (daddroleto)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options"),
                         parser_errposition(pstate, defel->location)));
            daddroleto = defel;
        }
        else if (strcmp(defel->defname, "rolemembers") == 0)
        {
            if (drolemembers)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options"),
                         parser_errposition(pstate, defel->location)));
            drolemembers = defel;
        }
        else if (strcmp(defel->defname, "adminmembers") == 0)
        {
            if (dadminmembers)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options"),
                         parser_errposition(pstate, defel->location)));
            dadminmembers = defel;
        }
        else if (strcmp(defel->defname, "validUntil") == 0)
        {
            if (dvalidUntil)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options"),
                         parser_errposition(pstate, defel->location)));
            dvalidUntil = defel;
        }
        else if (strcmp(defel->defname, "bypassrls") == 0)
        {
            if (dbypassRLS)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options"),
                         parser_errposition(pstate, defel->location)));
            dbypassRLS = defel;
        }
        else
            elog(ERROR, "option \"%s\" not recognized",
                 defel->defname);
    }

    if (dpassword && dpassword->arg)
        password = strVal(dpassword->arg);
    if (dissuper)
        issuper = intVal(dissuper->arg) != 0;
    if (dinherit)
        inherit = intVal(dinherit->arg) != 0;
    if (dcreaterole)
        createrole = intVal(dcreaterole->arg) != 0;
    if (dcreatedb)
        createdb = intVal(dcreatedb->arg) != 0;
    if (dcanlogin)
        canlogin = intVal(dcanlogin->arg) != 0;
    if (disreplication)
        isreplication = intVal(disreplication->arg) != 0;
    if (dconnlimit)
    {
        connlimit = intVal(dconnlimit->arg);
        if (connlimit < -1)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                     errmsg("invalid connection limit: %d", connlimit)));
    }
    if (daddroleto)
        addroleto = (List *) daddroleto->arg;
    if (drolemembers)
        rolemembers = (List *) drolemembers->arg;
    if (dadminmembers)
        adminmembers = (List *) dadminmembers->arg;
    if (dvalidUntil)
        validUntil = strVal(dvalidUntil->arg);
    if (dbypassRLS)
        bypassrls = intVal(dbypassRLS->arg) != 0;

    /* Check some permissions first */
    if (issuper)
    {
        if (!superuser())
            ereport(ERROR,
                    (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                     errmsg("must be superuser to create superusers")));
    }
    else if (isreplication)
    {
        if (!superuser())
            ereport(ERROR,
                    (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                     errmsg("must be superuser to create replication users")));
    }
    else if (bypassrls)
    {
        if (!superuser())
            ereport(ERROR,
                    (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                     errmsg("must be superuser to change bypassrls attribute")));
    }
    else
    {
        if (!have_createrole_privilege())
            ereport(ERROR,
                    (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                     errmsg("permission denied to create role")));
    }

    /*
     * Check that the user is not trying to create a role in the reserved
     * "pg_" namespace.
     */
    if (IsReservedName(stmt->role))
        ereport(ERROR,
                (errcode(ERRCODE_RESERVED_NAME),
                 errmsg("role name \"%s\" is reserved",
                        stmt->role),
                 errdetail("Role names starting with \"pg_\" are reserved.")));

    /*
     * If built with appropriate switch, whine when regression-testing
     * conventions for role names are violated.
     */
#ifdef ENFORCE_REGRESSION_TEST_NAME_RESTRICTIONS
    if (strncmp(stmt->role, "regress_", 8) != 0)
        elog(WARNING, "roles created by regression test cases should have names starting with \"regress_\"");
#endif

    /*
     * Check the pg_authid relation to be certain the role doesn't already
     * exist.
     */
    pg_authid_rel = table_open(AuthIdRelationId, RowExclusiveLock);
    pg_authid_dsc = RelationGetDescr(pg_authid_rel);

    if (OidIsValid(get_role_oid(stmt->role, true)))
        ereport(ERROR,
                (errcode(ERRCODE_DUPLICATE_OBJECT),
                 errmsg("role \"%s\" already exists",
                        stmt->role)));

    /* Convert validuntil to internal form */
    if (validUntil)
    {
        validUntil_datum = DirectFunctionCall3(timestamptz_in,
                                               CStringGetDatum(validUntil),
                                               ObjectIdGetDatum(InvalidOid),
                                               Int32GetDatum(-1));
        validUntil_null = false;
    }
    else
    {
        validUntil_datum = (Datum) 0;
        validUntil_null = true;
    }

    /*
     * Call the password checking hook if there is one defined
     */
    if (check_password_hook && password)
        (*check_password_hook) (stmt->role,
                                password,
                                get_password_type(password),
                                validUntil_datum,
                                validUntil_null);

    /*
     * Build a tuple to insert
     */
    MemSet(new_record, 0, sizeof(new_record));
    MemSet(new_record_nulls, false, sizeof(new_record_nulls));

    new_record[Anum_pg_authid_rolname - 1] =
        DirectFunctionCall1(namein, CStringGetDatum(stmt->role));

    new_record[Anum_pg_authid_rolsuper - 1] = BoolGetDatum(issuper);
    new_record[Anum_pg_authid_rolinherit - 1] = BoolGetDatum(inherit);
    new_record[Anum_pg_authid_rolcreaterole - 1] = BoolGetDatum(createrole);
    new_record[Anum_pg_authid_rolcreatedb - 1] = BoolGetDatum(createdb);
    new_record[Anum_pg_authid_rolcanlogin - 1] = BoolGetDatum(canlogin);
    new_record[Anum_pg_authid_rolreplication - 1] = BoolGetDatum(isreplication);
    new_record[Anum_pg_authid_rolconnlimit - 1] = Int32GetDatum(connlimit);

    if (password)
    {
        char       *shadow_pass;
        char       *logdetail;

        /*
         * Don't allow an empty password. Libpq treats an empty password the
         * same as no password at all, and won't even try to authenticate. But
         * other clients might, so allowing it would be confusing. By clearing
         * the password when an empty string is specified, the account is
         * consistently locked for all clients.
         *
         * Note that this only covers passwords stored in the database itself.
         * There are also checks in the authentication code, to forbid an
         * empty password from being used with authentication methods that
         * fetch the password from an external system, like LDAP or PAM.
         */
        if (password[0] == '\0' ||
            plain_crypt_verify(stmt->role, password, "", &logdetail) == STATUS_OK)
        {
            ereport(NOTICE,
                    (errmsg("empty string is not a valid password, clearing password")));
            new_record_nulls[Anum_pg_authid_rolpassword - 1] = true;
        }
        else
        {
            /* Encrypt the password to the requested format. */
            shadow_pass = encrypt_password(Password_encryption, stmt->role,
                                           password);
            new_record[Anum_pg_authid_rolpassword - 1] =
                CStringGetTextDatum(shadow_pass);
        }
    }
    else
        new_record_nulls[Anum_pg_authid_rolpassword - 1] = true;

    new_record[Anum_pg_authid_rolvaliduntil - 1] = validUntil_datum;
    new_record_nulls[Anum_pg_authid_rolvaliduntil - 1] = validUntil_null;

    new_record[Anum_pg_authid_rolbypassrls - 1] = BoolGetDatum(bypassrls);

    /*
     * pg_largeobject_metadata contains pg_authid.oid's, so we use the
     * binary-upgrade override.
     */
    if (IsBinaryUpgrade)
    {
        if (!OidIsValid(binary_upgrade_next_pg_authid_oid))
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                     errmsg("pg_authid OID value not set when in binary upgrade mode")));

        roleid = binary_upgrade_next_pg_authid_oid;
        binary_upgrade_next_pg_authid_oid = InvalidOid;
    }
    else
    {
        roleid = GetNewOidWithIndex(pg_authid_rel, AuthIdOidIndexId,
                                    Anum_pg_authid_oid);
    }

    new_record[Anum_pg_authid_oid - 1] = ObjectIdGetDatum(roleid);

    tuple = heap_form_tuple(pg_authid_dsc, new_record, new_record_nulls);

    /*
     * Insert new record in the pg_authid table
     */
    CatalogTupleInsert(pg_authid_rel, tuple);

    /*
     * Advance command counter so we can see new record; else tests in
     * AddRoleMems may fail.
     */
    if (addroleto || adminmembers || rolemembers)
        CommandCounterIncrement();

    /*
     * Add the new role to the specified existing roles.
     */
    foreach(item, addroleto)
    {
        RoleSpec   *oldrole = lfirst(item);
        HeapTuple   oldroletup = get_rolespec_tuple(oldrole);
        Form_pg_authid oldroleform = (Form_pg_authid) GETSTRUCT(oldroletup);
        Oid         oldroleid = oldroleform->oid;
        char       *oldrolename = NameStr(oldroleform->rolname);

        AddRoleMems(oldrolename, oldroleid,
                    list_make1(makeString(stmt->role)),
                    list_make1_oid(roleid),
                    GetUserId(), false);

        ReleaseSysCache(oldroletup);
    }

    /*
     * Add the specified members to this new role. adminmembers get the admin
     * option, rolemembers don't.
     */
    AddRoleMems(stmt->role, roleid,
                adminmembers, roleSpecsToIds(adminmembers),
                GetUserId(), true);
    AddRoleMems(stmt->role, roleid,
                rolemembers, roleSpecsToIds(rolemembers),
                GetUserId(), false);

    /* Post creation hook for new role */
    InvokeObjectPostCreateHook(AuthIdRelationId, roleid, 0);

    /*
     * Close pg_authid, but keep lock till commit.
     */
    table_close(pg_authid_rel, NoLock);

    return roleid;
}


/*
 * ALTER ROLE
 *
 * Note: the rolemembers option accepted here is intended to support the
 * backwards-compatible ALTER GROUP syntax.  Although it will work to say
 * "ALTER ROLE role ROLE rolenames", we don't document it.
 */
Oid
AlterRole(AlterRoleStmt *stmt)
{
    Datum       new_record[Natts_pg_authid];
    bool        new_record_nulls[Natts_pg_authid];
    bool        new_record_repl[Natts_pg_authid];
    Relation    pg_authid_rel;
    TupleDesc   pg_authid_dsc;
    HeapTuple   tuple,
                new_tuple;
    Form_pg_authid authform;
    ListCell   *option;
    char       *rolename = NULL;
    char       *password = NULL;    /* user password */
    int         issuper = -1;   /* Make the user a superuser? */
    int         inherit = -1;   /* Auto inherit privileges? */
    int         createrole = -1;    /* Can this user create roles? */
    int         createdb = -1;  /* Can the user create databases? */
    int         canlogin = -1;  /* Can this user login? */
    int         isreplication = -1; /* Is this a replication role? */
    int         connlimit = -1; /* maximum connections allowed */
    List       *rolemembers = NIL;  /* roles to be added/removed */
    char       *validUntil = NULL;  /* time the login is valid until */
    Datum       validUntil_datum;   /* same, as timestamptz Datum */
    bool        validUntil_null;
    int         bypassrls = -1;
    DefElem    *dpassword = NULL;
    DefElem    *dissuper = NULL;
    DefElem    *dinherit = NULL;
    DefElem    *dcreaterole = NULL;
    DefElem    *dcreatedb = NULL;
    DefElem    *dcanlogin = NULL;
    DefElem    *disreplication = NULL;
    DefElem    *dconnlimit = NULL;
    DefElem    *drolemembers = NULL;
    DefElem    *dvalidUntil = NULL;
    DefElem    *dbypassRLS = NULL;
    Oid         roleid;

    check_rolespec_name(stmt->role,
                        "Cannot alter reserved roles.");

    /* Extract options from the statement node tree */
    foreach(option, stmt->options)
    {
        DefElem    *defel = (DefElem *) lfirst(option);

        if (strcmp(defel->defname, "password") == 0)
        {
            if (dpassword)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options")));
            dpassword = defel;
        }
        else if (strcmp(defel->defname, "superuser") == 0)
        {
            if (dissuper)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options")));
            dissuper = defel;
        }
        else if (strcmp(defel->defname, "inherit") == 0)
        {
            if (dinherit)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options")));
            dinherit = defel;
        }
        else if (strcmp(defel->defname, "createrole") == 0)
        {
            if (dcreaterole)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options")));
            dcreaterole = defel;
        }
        else if (strcmp(defel->defname, "createdb") == 0)
        {
            if (dcreatedb)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options")));
            dcreatedb = defel;
        }
        else if (strcmp(defel->defname, "canlogin") == 0)
        {
            if (dcanlogin)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options")));
            dcanlogin = defel;
        }
        else if (strcmp(defel->defname, "isreplication") == 0)
        {
            if (disreplication)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options")));
            disreplication = defel;
        }
        else if (strcmp(defel->defname, "connectionlimit") == 0)
        {
            if (dconnlimit)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options")));
            dconnlimit = defel;
        }
        else if (strcmp(defel->defname, "rolemembers") == 0 &&
                 stmt->action != 0)
        {
            if (drolemembers)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options")));
            drolemembers = defel;
        }
        else if (strcmp(defel->defname, "validUntil") == 0)
        {
            if (dvalidUntil)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options")));
            dvalidUntil = defel;
        }
        else if (strcmp(defel->defname, "bypassrls") == 0)
        {
            if (dbypassRLS)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options")));
            dbypassRLS = defel;
        }
        else
            elog(ERROR, "option \"%s\" not recognized",
                 defel->defname);
    }

    if (dpassword && dpassword->arg)
        password = strVal(dpassword->arg);
    if (dissuper)
        issuper = intVal(dissuper->arg);
    if (dinherit)
        inherit = intVal(dinherit->arg);
    if (dcreaterole)
        createrole = intVal(dcreaterole->arg);
    if (dcreatedb)
        createdb = intVal(dcreatedb->arg);
    if (dcanlogin)
        canlogin = intVal(dcanlogin->arg);
    if (disreplication)
        isreplication = intVal(disreplication->arg);
    if (dconnlimit)
    {
        connlimit = intVal(dconnlimit->arg);
        if (connlimit < -1)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                     errmsg("invalid connection limit: %d", connlimit)));
    }
    if (drolemembers)
        rolemembers = (List *) drolemembers->arg;
    if (dvalidUntil)
        validUntil = strVal(dvalidUntil->arg);
    if (dbypassRLS)
        bypassrls = intVal(dbypassRLS->arg);

    /*
     * Scan the pg_authid relation to be certain the user exists.
     */
    pg_authid_rel = table_open(AuthIdRelationId, RowExclusiveLock);
    pg_authid_dsc = RelationGetDescr(pg_authid_rel);

    tuple = get_rolespec_tuple(stmt->role);
    authform = (Form_pg_authid) GETSTRUCT(tuple);
    rolename = pstrdup(NameStr(authform->rolname));
    roleid = authform->oid;

    /*
     * To mess with a superuser you gotta be superuser; else you need
     * createrole, or just want to change your own password
     */
    if (authform->rolsuper || issuper >= 0)
    {
        if (!superuser())
            ereport(ERROR,
                    (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                     errmsg("must be superuser to alter superusers")));
    }
    else if (authform->rolreplication || isreplication >= 0)
    {
        if (!superuser())
            ereport(ERROR,
                    (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                     errmsg("must be superuser to alter replication users")));
    }
    else if (authform->rolbypassrls || bypassrls >= 0)
    {
        if (!superuser())
            ereport(ERROR,
                    (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                     errmsg("must be superuser to change bypassrls attribute")));
    }
    else if (!have_createrole_privilege())
    {
        if (!(inherit < 0 &&
              createrole < 0 &&
              createdb < 0 &&
              canlogin < 0 &&
              isreplication < 0 &&
              !dconnlimit &&
              !rolemembers &&
              !validUntil &&
              dpassword &&
              roleid == GetUserId()))
            ereport(ERROR,
                    (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                     errmsg("permission denied")));
    }

    /* Convert validuntil to internal form */
    if (validUntil)
    {
        validUntil_datum = DirectFunctionCall3(timestamptz_in,
                                               CStringGetDatum(validUntil),
                                               ObjectIdGetDatum(InvalidOid),
                                               Int32GetDatum(-1));
        validUntil_null = false;
    }
    else
    {
        /* fetch existing setting in case hook needs it */
        validUntil_datum = SysCacheGetAttr(AUTHNAME, tuple,
                                           Anum_pg_authid_rolvaliduntil,
                                           &validUntil_null);
    }

    /*
     * Call the password checking hook if there is one defined
     */
    if (check_password_hook && password)
        (*check_password_hook) (rolename,
                                password,
                                get_password_type(password),
                                validUntil_datum,
                                validUntil_null);

    /*
     * Build an updated tuple, perusing the information just obtained
     */
    MemSet(new_record, 0, sizeof(new_record));
    MemSet(new_record_nulls, false, sizeof(new_record_nulls));
    MemSet(new_record_repl, false, sizeof(new_record_repl));

    /*
     * issuper/createrole/etc
     */
    if (issuper >= 0)
    {
        new_record[Anum_pg_authid_rolsuper - 1] = BoolGetDatum(issuper > 0);
        new_record_repl[Anum_pg_authid_rolsuper - 1] = true;
    }

    if (inherit >= 0)
    {
        new_record[Anum_pg_authid_rolinherit - 1] = BoolGetDatum(inherit > 0);
        new_record_repl[Anum_pg_authid_rolinherit - 1] = true;
    }

    if (createrole >= 0)
    {
        new_record[Anum_pg_authid_rolcreaterole - 1] = BoolGetDatum(createrole > 0);
        new_record_repl[Anum_pg_authid_rolcreaterole - 1] = true;
    }

    if (createdb >= 0)
    {
        new_record[Anum_pg_authid_rolcreatedb - 1] = BoolGetDatum(createdb > 0);
        new_record_repl[Anum_pg_authid_rolcreatedb - 1] = true;
    }

    if (canlogin >= 0)
    {
        new_record[Anum_pg_authid_rolcanlogin - 1] = BoolGetDatum(canlogin > 0);
        new_record_repl[Anum_pg_authid_rolcanlogin - 1] = true;
    }

    if (isreplication >= 0)
    {
        new_record[Anum_pg_authid_rolreplication - 1] = BoolGetDatum(isreplication > 0);
        new_record_repl[Anum_pg_authid_rolreplication - 1] = true;
    }

    if (dconnlimit)
    {
        new_record[Anum_pg_authid_rolconnlimit - 1] = Int32GetDatum(connlimit);
        new_record_repl[Anum_pg_authid_rolconnlimit - 1] = true;
    }

    /* password */
    if (password)
    {
        char       *shadow_pass;
        char       *logdetail;

        /* Like in CREATE USER, don't allow an empty password. */
        if (password[0] == '\0' ||
            plain_crypt_verify(rolename, password, "", &logdetail) == STATUS_OK)
        {
            ereport(NOTICE,
                    (errmsg("empty string is not a valid password, clearing password")));
            new_record_nulls[Anum_pg_authid_rolpassword - 1] = true;
        }
        else
        {
            /* Encrypt the password to the requested format. */
            shadow_pass = encrypt_password(Password_encryption, rolename,
                                           password);
            new_record[Anum_pg_authid_rolpassword - 1] =
                CStringGetTextDatum(shadow_pass);
        }
        new_record_repl[Anum_pg_authid_rolpassword - 1] = true;
    }

    /* unset password */
    if (dpassword && dpassword->arg == NULL)
    {
        new_record_repl[Anum_pg_authid_rolpassword - 1] = true;
        new_record_nulls[Anum_pg_authid_rolpassword - 1] = true;
    }

    /* valid until */
    new_record[Anum_pg_authid_rolvaliduntil - 1] = validUntil_datum;
    new_record_nulls[Anum_pg_authid_rolvaliduntil - 1] = validUntil_null;
    new_record_repl[Anum_pg_authid_rolvaliduntil - 1] = true;

    if (bypassrls >= 0)
    {
        new_record[Anum_pg_authid_rolbypassrls - 1] = BoolGetDatum(bypassrls > 0);
        new_record_repl[Anum_pg_authid_rolbypassrls - 1] = true;
    }

    new_tuple = heap_modify_tuple(tuple, pg_authid_dsc, new_record,
                                  new_record_nulls, new_record_repl);
    CatalogTupleUpdate(pg_authid_rel, &tuple->t_self, new_tuple);

    InvokeObjectPostAlterHook(AuthIdRelationId, roleid, 0);

    ReleaseSysCache(tuple);
    heap_freetuple(new_tuple);

    /*
     * Advance command counter so we can see new record; else tests in
     * AddRoleMems may fail.
     */
    if (rolemembers)
        CommandCounterIncrement();

    if (stmt->action == +1)     /* add members to role */
        AddRoleMems(rolename, roleid,
                    rolemembers, roleSpecsToIds(rolemembers),
                    GetUserId(), false);
    else if (stmt->action == -1)    /* drop members from role */
        DelRoleMems(rolename, roleid,
                    rolemembers, roleSpecsToIds(rolemembers),
                    false);

    /*
     * Close pg_authid, but keep lock till commit.
     */
    table_close(pg_authid_rel, NoLock);

    return roleid;
}


/*
 * ALTER ROLE ... SET
 */
Oid
AlterRoleSet(AlterRoleSetStmt *stmt)
{
    HeapTuple   roletuple;
    Form_pg_authid roleform;
    Oid         databaseid = InvalidOid;
    Oid         roleid = InvalidOid;

    if (stmt->role)
    {
        check_rolespec_name(stmt->role,
                            "Cannot alter reserved roles.");

        roletuple = get_rolespec_tuple(stmt->role);
        roleform = (Form_pg_authid) GETSTRUCT(roletuple);
        roleid = roleform->oid;

        /*
         * Obtain a lock on the role and make sure it didn't go away in the
         * meantime.
         */
        shdepLockAndCheckObject(AuthIdRelationId, roleid);

        /*
         * To mess with a superuser you gotta be superuser; else you need
         * createrole, or just want to change your own settings
         */
        if (roleform->rolsuper)
        {
            if (!superuser())
                ereport(ERROR,
                        (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                         errmsg("must be superuser to alter superusers")));
        }
        else
        {
            if (!have_createrole_privilege() && roleid != GetUserId())
                ereport(ERROR,
                        (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                         errmsg("permission denied")));
        }

        ReleaseSysCache(roletuple);
    }

    /* look up and lock the database, if specified */
    if (stmt->database != NULL)
    {
        databaseid = get_database_oid(stmt->database, false);
        shdepLockAndCheckObject(DatabaseRelationId, databaseid);

        if (!stmt->role)
        {
            /*
             * If no role is specified, then this is effectively the same as
             * ALTER DATABASE ... SET, so use the same permission check.
             */
            if (!pg_database_ownercheck(databaseid, GetUserId()))
                aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_DATABASE,
                               stmt->database);
        }
    }

    if (!stmt->role && !stmt->database)
    {
        /* Must be superuser to alter settings globally. */
        if (!superuser())
            ereport(ERROR,
                    (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                     errmsg("must be superuser to alter settings globally")));
    }

    AlterSetting(databaseid, roleid, stmt->setstmt);

    return roleid;
}


/*
 * DROP ROLE
 */
void
DropRole(DropRoleStmt *stmt)
{
    Relation    pg_authid_rel,
                pg_auth_members_rel;
    ListCell   *item;

    if (!have_createrole_privilege())
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                 errmsg("permission denied to drop role")));

    /*
     * Scan the pg_authid relation to find the Oid of the role(s) to be
     * deleted.
     */
    pg_authid_rel = table_open(AuthIdRelationId, RowExclusiveLock);
    pg_auth_members_rel = table_open(AuthMemRelationId, RowExclusiveLock);

    foreach(item, stmt->roles)
    {
        RoleSpec   *rolspec = lfirst(item);
        char       *role;
        HeapTuple   tuple,
                    tmp_tuple;
        Form_pg_authid roleform;
        ScanKeyData scankey;
        char       *detail;
        char       *detail_log;
        SysScanDesc sscan;
        Oid         roleid;

        if (rolspec->roletype != ROLESPEC_CSTRING)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                     errmsg("cannot use special role specifier in DROP ROLE")));
        role = rolspec->rolename;

        tuple = SearchSysCache1(AUTHNAME, PointerGetDatum(role));
        if (!HeapTupleIsValid(tuple))
        {
            if (!stmt->missing_ok)
            {
                ereport(ERROR,
                        (errcode(ERRCODE_UNDEFINED_OBJECT),
                         errmsg("role \"%s\" does not exist", role)));
            }
            else
            {
                ereport(NOTICE,
                        (errmsg("role \"%s\" does not exist, skipping",
                                role)));
            }

            continue;
        }

        roleform = (Form_pg_authid) GETSTRUCT(tuple);
        roleid = roleform->oid;

        if (roleid == GetUserId())
            ereport(ERROR,
                    (errcode(ERRCODE_OBJECT_IN_USE),
                     errmsg("current user cannot be dropped")));
        if (roleid == GetOuterUserId())
            ereport(ERROR,
                    (errcode(ERRCODE_OBJECT_IN_USE),
                     errmsg("current user cannot be dropped")));
        if (roleid == GetSessionUserId())
            ereport(ERROR,
                    (errcode(ERRCODE_OBJECT_IN_USE),
                     errmsg("session user cannot be dropped")));

        /*
         * For safety's sake, we allow createrole holders to drop ordinary
         * roles but not superuser roles.  This is mainly to avoid the
         * scenario where you accidentally drop the last superuser.
         */
        if (roleform->rolsuper && !superuser())
            ereport(ERROR,
                    (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                     errmsg("must be superuser to drop superusers")));

        /* DROP hook for the role being removed */
        InvokeObjectDropHook(AuthIdRelationId, roleid, 0);

        /*
         * Lock the role, so nobody can add dependencies to her while we drop
         * her.  We keep the lock until the end of transaction.
         */
        LockSharedObject(AuthIdRelationId, roleid, 0, AccessExclusiveLock);

        /* Check for pg_shdepend entries depending on this role */
        if (checkSharedDependencies(AuthIdRelationId, roleid,
                                    &detail, &detail_log))
            ereport(ERROR,
                    (errcode(ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST),
                     errmsg("role \"%s\" cannot be dropped because some objects depend on it",
                            role),
                     errdetail_internal("%s", detail),
                     errdetail_log("%s", detail_log)));

        /*
         * Remove the role from the pg_authid table
         */
        CatalogTupleDelete(pg_authid_rel, &tuple->t_self);

        ReleaseSysCache(tuple);

        /*
         * Remove role from the pg_auth_members table.  We have to remove all
         * tuples that show it as either a role or a member.
         *
         * XXX what about grantor entries?  Maybe we should do one heap scan.
         */
        ScanKeyInit(&scankey,
                    Anum_pg_auth_members_roleid,
                    BTEqualStrategyNumber, F_OIDEQ,
                    ObjectIdGetDatum(roleid));

        sscan = systable_beginscan(pg_auth_members_rel, AuthMemRoleMemIndexId,
                                   true, NULL, 1, &scankey);

        while (HeapTupleIsValid(tmp_tuple = systable_getnext(sscan)))
        {
            CatalogTupleDelete(pg_auth_members_rel, &tmp_tuple->t_self);
        }

        systable_endscan(sscan);

        ScanKeyInit(&scankey,
                    Anum_pg_auth_members_member,
                    BTEqualStrategyNumber, F_OIDEQ,
                    ObjectIdGetDatum(roleid));

        sscan = systable_beginscan(pg_auth_members_rel, AuthMemMemRoleIndexId,
                                   true, NULL, 1, &scankey);

        while (HeapTupleIsValid(tmp_tuple = systable_getnext(sscan)))
        {
            CatalogTupleDelete(pg_auth_members_rel, &tmp_tuple->t_self);
        }

        systable_endscan(sscan);

        /*
         * Remove any comments or security labels on this role.
         */
        DeleteSharedComments(roleid, AuthIdRelationId);
        DeleteSharedSecurityLabel(roleid, AuthIdRelationId);

        /*
         * Remove settings for this role.
         */
        DropSetting(InvalidOid, roleid);

        /*
         * Advance command counter so that later iterations of this loop will
         * see the changes already made.  This is essential if, for example,
         * we are trying to drop both a role and one of its direct members ---
         * we'll get an error if we try to delete the linking pg_auth_members
         * tuple twice.  (We do not need a CCI between the two delete loops
         * above, because it's not allowed for a role to directly contain
         * itself.)
         */
        CommandCounterIncrement();
    }

    /*
     * Now we can clean up; but keep locks until commit.
     */
    table_close(pg_auth_members_rel, NoLock);
    table_close(pg_authid_rel, NoLock);
}

/*
 * Rename role
 */
ObjectAddress
RenameRole(const char *oldname, const char *newname)
{
    HeapTuple   oldtuple,
                newtuple;
    TupleDesc   dsc;
    Relation    rel;
    Datum       datum;
    bool        isnull;
    Datum       repl_val[Natts_pg_authid];
    bool        repl_null[Natts_pg_authid];
    bool        repl_repl[Natts_pg_authid];
    int         i;
    Oid         roleid;
    ObjectAddress address;
    Form_pg_authid authform;

    rel = table_open(AuthIdRelationId, RowExclusiveLock);
    dsc = RelationGetDescr(rel);

    oldtuple = SearchSysCache1(AUTHNAME, CStringGetDatum(oldname));
    if (!HeapTupleIsValid(oldtuple))
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_OBJECT),
                 errmsg("role \"%s\" does not exist", oldname)));

    /*
     * XXX Client applications probably store the session user somewhere, so
     * renaming it could cause confusion.  On the other hand, there may not be
     * an actual problem besides a little confusion, so think about this and
     * decide.  Same for SET ROLE ... we don't restrict renaming the current
     * effective userid, though.
     */

    authform = (Form_pg_authid) GETSTRUCT(oldtuple);
    roleid = authform->oid;

    if (roleid == GetSessionUserId())
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("session user cannot be renamed")));
    if (roleid == GetOuterUserId())
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("current user cannot be renamed")));

    /*
     * Check that the user is not trying to rename a system role and not
     * trying to rename a role into the reserved "pg_" namespace.
     */
    if (IsReservedName(NameStr(authform->rolname)))
        ereport(ERROR,
                (errcode(ERRCODE_RESERVED_NAME),
                 errmsg("role name \"%s\" is reserved",
                        NameStr(authform->rolname)),
                 errdetail("Role names starting with \"pg_\" are reserved.")));

    if (IsReservedName(newname))
        ereport(ERROR,
                (errcode(ERRCODE_RESERVED_NAME),
                 errmsg("role name \"%s\" is reserved",
                        newname),
                 errdetail("Role names starting with \"pg_\" are reserved.")));

    /*
     * If built with appropriate switch, whine when regression-testing
     * conventions for role names are violated.
     */
#ifdef ENFORCE_REGRESSION_TEST_NAME_RESTRICTIONS
    if (strncmp(newname, "regress_", 8) != 0)
        elog(WARNING, "roles created by regression test cases should have names starting with \"regress_\"");
#endif

    /* make sure the new name doesn't exist */
    if (SearchSysCacheExists1(AUTHNAME, CStringGetDatum(newname)))
        ereport(ERROR,
                (errcode(ERRCODE_DUPLICATE_OBJECT),
                 errmsg("role \"%s\" already exists", newname)));

    /*
     * createrole is enough privilege unless you want to mess with a superuser
     */
    if (((Form_pg_authid) GETSTRUCT(oldtuple))->rolsuper)
    {
        if (!superuser())
            ereport(ERROR,
                    (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                     errmsg("must be superuser to rename superusers")));
    }
    else
    {
        if (!have_createrole_privilege())
            ereport(ERROR,
                    (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                     errmsg("permission denied to rename role")));
    }

    /* OK, construct the modified tuple */
    for (i = 0; i < Natts_pg_authid; i++)
        repl_repl[i] = false;

    repl_repl[Anum_pg_authid_rolname - 1] = true;
    repl_val[Anum_pg_authid_rolname - 1] = DirectFunctionCall1(namein,
                                                               CStringGetDatum(newname));
    repl_null[Anum_pg_authid_rolname - 1] = false;

    datum = heap_getattr(oldtuple, Anum_pg_authid_rolpassword, dsc, &isnull);

    if (!isnull && get_password_type(TextDatumGetCString(datum)) == PASSWORD_TYPE_MD5)
    {
        /* MD5 uses the username as salt, so just clear it on a rename */
        repl_repl[Anum_pg_authid_rolpassword - 1] = true;
        repl_null[Anum_pg_authid_rolpassword - 1] = true;

        ereport(NOTICE,
                (errmsg("MD5 password cleared because of role rename")));
    }

    newtuple = heap_modify_tuple(oldtuple, dsc, repl_val, repl_null, repl_repl);
    CatalogTupleUpdate(rel, &oldtuple->t_self, newtuple);

    InvokeObjectPostAlterHook(AuthIdRelationId, roleid, 0);

    ObjectAddressSet(address, AuthIdRelationId, roleid);

    ReleaseSysCache(oldtuple);

    /*
     * Close pg_authid, but keep lock till commit.
     */
    table_close(rel, NoLock);

    return address;
}

/*
 * GrantRoleStmt
 *
 * Grant/Revoke roles to/from roles
 */
void
GrantRole(GrantRoleStmt *stmt)
{
    Relation    pg_authid_rel;
    Oid         grantor;
    List       *grantee_ids;
    ListCell   *item;

    if (stmt->grantor)
        grantor = get_rolespec_oid(stmt->grantor, false);
    else
        grantor = GetUserId();

    grantee_ids = roleSpecsToIds(stmt->grantee_roles);

    /* AccessShareLock is enough since we aren't modifying pg_authid */
    pg_authid_rel = table_open(AuthIdRelationId, AccessShareLock);

    /*
     * Step through all of the granted roles and add/remove entries for the
     * grantees, or, if admin_opt is set, then just add/remove the admin
     * option.
     *
     * Note: Permissions checking is done by AddRoleMems/DelRoleMems
     */
    foreach(item, stmt->granted_roles)
    {
        AccessPriv *priv = (AccessPriv *) lfirst(item);
        char       *rolename = priv->priv_name;
        Oid         roleid;

        /* Must reject priv(columns) and ALL PRIVILEGES(columns) */
        if (rolename == NULL || priv->cols != NIL)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_GRANT_OPERATION),
                     errmsg("column names cannot be included in GRANT/REVOKE ROLE")));

        roleid = get_role_oid(rolename, false);
        if (stmt->is_grant)
            AddRoleMems(rolename, roleid,
                        stmt->grantee_roles, grantee_ids,
                        grantor, stmt->admin_opt);
        else
            DelRoleMems(rolename, roleid,
                        stmt->grantee_roles, grantee_ids,
                        stmt->admin_opt);
    }

    /*
     * Close pg_authid, but keep lock till commit.
     */
    table_close(pg_authid_rel, NoLock);
}

/*
 * DropOwnedObjects
 *
 * Drop the objects owned by a given list of roles.
 */
void
DropOwnedObjects(DropOwnedStmt *stmt)
{
    List       *role_ids = roleSpecsToIds(stmt->roles);
    ListCell   *cell;

    /* Check privileges */
    foreach(cell, role_ids)
    {
        Oid         roleid = lfirst_oid(cell);

        if (!has_privs_of_role(GetUserId(), roleid))
            ereport(ERROR,
                    (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                     errmsg("permission denied to drop objects")));
    }

    /* Ok, do it */
    shdepDropOwned(role_ids, stmt->behavior);
}

/*
 * ReassignOwnedObjects
 *
 * Give the objects owned by a given list of roles away to another user.
 */
void
ReassignOwnedObjects(ReassignOwnedStmt *stmt)
{
    List       *role_ids = roleSpecsToIds(stmt->roles);
    ListCell   *cell;
    Oid         newrole;

    /* Check privileges */
    foreach(cell, role_ids)
    {
        Oid         roleid = lfirst_oid(cell);

        if (!has_privs_of_role(GetUserId(), roleid))
            ereport(ERROR,
                    (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                     errmsg("permission denied to reassign objects")));
    }

    /* Must have privileges on the receiving side too */
    newrole = get_rolespec_oid(stmt->newrole, false);

    if (!has_privs_of_role(GetUserId(), newrole))
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                 errmsg("permission denied to reassign objects")));

    /* Ok, do it */
    shdepReassignOwned(role_ids, newrole);
}

/*
 * roleSpecsToIds
 *
 * Given a list of RoleSpecs, generate a list of role OIDs in the same order.
 *
 * ROLESPEC_PUBLIC is not allowed.
 */
List *
roleSpecsToIds(List *memberNames)
{
    List       *result = NIL;
    ListCell   *l;

    foreach(l, memberNames)
    {
        RoleSpec   *rolespec = lfirst_node(RoleSpec, l);
        Oid         roleid;

        roleid = get_rolespec_oid(rolespec, false);
        result = lappend_oid(result, roleid);
    }
    return result;
}

/*
 * AddRoleMems -- Add given members to the specified role
 *
 * rolename: name of role to add to (used only for error messages)
 * roleid: OID of role to add to
 * memberSpecs: list of RoleSpec of roles to add (used only for error messages)
 * memberIds: OIDs of roles to add
 * grantorId: who is granting the membership
 * admin_opt: granting admin option?
 *
 * Note: caller is responsible for calling auth_file_update_needed().
 */
static void
AddRoleMems(const char *rolename, Oid roleid,
            List *memberSpecs, List *memberIds,
            Oid grantorId, bool admin_opt)
{
    Relation    pg_authmem_rel;
    TupleDesc   pg_authmem_dsc;
    ListCell   *specitem;
    ListCell   *iditem;

    Assert(list_length(memberSpecs) == list_length(memberIds));

    /* Skip permission check if nothing to do */
    if (!memberIds)
        return;

    /*
     * Check permissions: must have createrole or admin option on the role to
     * be changed.  To mess with a superuser role, you gotta be superuser.
     */
    if (superuser_arg(roleid))
    {
        if (!superuser())
            ereport(ERROR,
                    (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                     errmsg("must be superuser to alter superusers")));
    }
    else
    {
        if (!have_createrole_privilege() &&
            !is_admin_of_role(grantorId, roleid))
            ereport(ERROR,
                    (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                     errmsg("must have admin option on role \"%s\"",
                            rolename)));
    }

    /*
     * The role membership grantor of record has little significance at
     * present.  Nonetheless, inasmuch as users might look to it for a crude
     * audit trail, let only superusers impute the grant to a third party.
     *
     * Before lifting this restriction, give the member == role case of
     * is_admin_of_role() a fresh look.  Ensure that the current role cannot
     * use an explicit grantor specification to take advantage of the session
     * user's self-admin right.
     */
    if (grantorId != GetUserId() && !superuser())
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                 errmsg("must be superuser to set grantor")));

    pg_authmem_rel = table_open(AuthMemRelationId, RowExclusiveLock);
    pg_authmem_dsc = RelationGetDescr(pg_authmem_rel);

    forboth(specitem, memberSpecs, iditem, memberIds)
    {
        RoleSpec   *memberRole = lfirst(specitem);
        Oid         memberid = lfirst_oid(iditem);
        HeapTuple   authmem_tuple;
        HeapTuple   tuple;
        Datum       new_record[Natts_pg_auth_members];
        bool        new_record_nulls[Natts_pg_auth_members];
        bool        new_record_repl[Natts_pg_auth_members];

        /*
         * Refuse creation of membership loops, including the trivial case
         * where a role is made a member of itself.  We do this by checking to
         * see if the target role is already a member of the proposed member
         * role.  We have to ignore possible superuserness, however, else we
         * could never grant membership in a superuser-privileged role.
         */
        if (is_member_of_role_nosuper(roleid, memberid))
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_GRANT_OPERATION),
                     (errmsg("role \"%s\" is a member of role \"%s\"",
                             rolename, get_rolespec_name(memberRole)))));

        /*
         * Check if entry for this role/member already exists; if so, give
         * warning unless we are adding admin option.
         */
        authmem_tuple = SearchSysCache2(AUTHMEMROLEMEM,
                                        ObjectIdGetDatum(roleid),
                                        ObjectIdGetDatum(memberid));
        if (HeapTupleIsValid(authmem_tuple) &&
            (!admin_opt ||
             ((Form_pg_auth_members) GETSTRUCT(authmem_tuple))->admin_option))
        {
            ereport(NOTICE,
                    (errmsg("role \"%s\" is already a member of role \"%s\"",
                            get_rolespec_name(memberRole), rolename)));
            ReleaseSysCache(authmem_tuple);
            continue;
        }

        /* Build a tuple to insert or update */
        MemSet(new_record, 0, sizeof(new_record));
        MemSet(new_record_nulls, false, sizeof(new_record_nulls));
        MemSet(new_record_repl, false, sizeof(new_record_repl));

        new_record[Anum_pg_auth_members_roleid - 1] = ObjectIdGetDatum(roleid);
        new_record[Anum_pg_auth_members_member - 1] = ObjectIdGetDatum(memberid);
        new_record[Anum_pg_auth_members_grantor - 1] = ObjectIdGetDatum(grantorId);
        new_record[Anum_pg_auth_members_admin_option - 1] = BoolGetDatum(admin_opt);

        if (HeapTupleIsValid(authmem_tuple))
        {
            new_record_repl[Anum_pg_auth_members_grantor - 1] = true;
            new_record_repl[Anum_pg_auth_members_admin_option - 1] = true;
            tuple = heap_modify_tuple(authmem_tuple, pg_authmem_dsc,
                                      new_record,
                                      new_record_nulls, new_record_repl);
            CatalogTupleUpdate(pg_authmem_rel, &tuple->t_self, tuple);
            ReleaseSysCache(authmem_tuple);
        }
        else
        {
            tuple = heap_form_tuple(pg_authmem_dsc,
                                    new_record, new_record_nulls);
            CatalogTupleInsert(pg_authmem_rel, tuple);
        }

        /* CCI after each change, in case there are duplicates in list */
        CommandCounterIncrement();
    }

    /*
     * Close pg_authmem, but keep lock till commit.
     */
    table_close(pg_authmem_rel, NoLock);
}

/*
 * DelRoleMems -- Remove given members from the specified role
 *
 * rolename: name of role to del from (used only for error messages)
 * roleid: OID of role to del from
 * memberSpecs: list of RoleSpec of roles to del (used only for error messages)
 * memberIds: OIDs of roles to del
 * admin_opt: remove admin option only?
 *
 * Note: caller is responsible for calling auth_file_update_needed().
 */
static void
DelRoleMems(const char *rolename, Oid roleid,
            List *memberSpecs, List *memberIds,
            bool admin_opt)
{
    Relation    pg_authmem_rel;
    TupleDesc   pg_authmem_dsc;
    ListCell   *specitem;
    ListCell   *iditem;

    Assert(list_length(memberSpecs) == list_length(memberIds));

    /* Skip permission check if nothing to do */
    if (!memberIds)
        return;

    /*
     * Check permissions: must have createrole or admin option on the role to
     * be changed.  To mess with a superuser role, you gotta be superuser.
     */
    if (superuser_arg(roleid))
    {
        if (!superuser())
            ereport(ERROR,
                    (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                     errmsg("must be superuser to alter superusers")));
    }
    else
    {
        if (!have_createrole_privilege() &&
            !is_admin_of_role(GetUserId(), roleid))
            ereport(ERROR,
                    (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                     errmsg("must have admin option on role \"%s\"",
                            rolename)));
    }

    pg_authmem_rel = table_open(AuthMemRelationId, RowExclusiveLock);
    pg_authmem_dsc = RelationGetDescr(pg_authmem_rel);

    forboth(specitem, memberSpecs, iditem, memberIds)
    {
        RoleSpec   *memberRole = lfirst(specitem);
        Oid         memberid = lfirst_oid(iditem);
        HeapTuple   authmem_tuple;

        /*
         * Find entry for this role/member
         */
        authmem_tuple = SearchSysCache2(AUTHMEMROLEMEM,
                                        ObjectIdGetDatum(roleid),
                                        ObjectIdGetDatum(memberid));
        if (!HeapTupleIsValid(authmem_tuple))
        {
            ereport(WARNING,
                    (errmsg("role \"%s\" is not a member of role \"%s\"",
                            get_rolespec_name(memberRole), rolename)));
            continue;
        }

        if (!admin_opt)
        {
            /* Remove the entry altogether */
            CatalogTupleDelete(pg_authmem_rel, &authmem_tuple->t_self);
        }
        else
        {
            /* Just turn off the admin option */
            HeapTuple   tuple;
            Datum       new_record[Natts_pg_auth_members];
            bool        new_record_nulls[Natts_pg_auth_members];
            bool        new_record_repl[Natts_pg_auth_members];

            /* Build a tuple to update with */
            MemSet(new_record, 0, sizeof(new_record));
            MemSet(new_record_nulls, false, sizeof(new_record_nulls));
            MemSet(new_record_repl, false, sizeof(new_record_repl));

            new_record[Anum_pg_auth_members_admin_option - 1] = BoolGetDatum(false);
            new_record_repl[Anum_pg_auth_members_admin_option - 1] = true;

            tuple = heap_modify_tuple(authmem_tuple, pg_authmem_dsc,
                                      new_record,
                                      new_record_nulls, new_record_repl);
            CatalogTupleUpdate(pg_authmem_rel, &tuple->t_self, tuple);
        }

        ReleaseSysCache(authmem_tuple);

        /* CCI after each change, in case there are duplicates in list */
        CommandCounterIncrement();
    }

    /*
     * Close pg_authmem, but keep lock till commit.
     */
    table_close(pg_authmem_rel, NoLock);
}